The separation of various hydrocarbonaceous compounds through the use of selective adsorbents is widespread in the petroleum, chemical, and petrochemical industries. Adsorption is often utilized when it is more difficult or expensive to separate the same compounds by other means such as fractionation. Examples of the types of separations which are often performed using selective adsorbents include the separation of ethylbenzene from a mixture of xylenes, unsaturated fatty acids from saturated fatty acids, fructose from glucose, acyclic olefins from acyclic paraffins, and normal paraffins from isoparaffins. Typically, the selectively adsorbed materials have the same number of carbon atoms per molecule as the non-selectively adsorbed materials and very similar boiling points. Another common application is the recovery of a particular class of hydrocarbons from a broad boiling point range mixture of two or more classes of hydrocarbons. An example is the separation of C10 to C14 normal paraffins from a mixture which also contains C10 to C14 isoparaffins.
The success of a particular adsorptive separation is determined by many factors. Predominant among these are the composition of the adsorbent (stationary phase) and desorbent (mobile phase) employed in the process. The remaining factors are basically related to process conditions, including operating conditions, feed stream composition, and the water content of the adsorbent.
There is a need for improved adsorption processes.